1. Field of the Invention
In general, the present invention relates to the structure of hand trucks and handcarts. More particularly, the present invention relates to hand trucks with adjustable frames that enable the hand truck to be converted into more than one configuration.
2. Prior Art Description
Hand trucks have many forms. However, the present invention relates to utility hand trucks of the type that are used by movers and package deliverymen to transport large and/or heavy objects. Such utility hand trucks typically have a flat protruding plate that can be slipped under a box or other heavy object. The plate is connected to a vertical framework. The vertical framework is supported by two wheels. The object to be lifted is typically strapped to the vertical framework. The vertical framework is then tilted backward out of the vertical plane. Leverage is transferred to the plate under the object and the object lifts off the ground. The weight of the object is now borne by the wheels of the hand truck. The object can therefore be moved by rolling the hand truck.
One of the largest drawbacks of a traditional hand truck is that the object being lifted by the hand truck must tilt with the framework of the hand truck in order for the weight of the object to be borne by the wheels of the hand truck. Not all heavy objects are convenient to tilt onto the framework of a hand track. For instance, large bulky objects, such as a piano cannot be safely balanced on a traditional hand truck. As a result, such objects must be lifted onto dollies and then moved using those dollies. This is a difficult, time consuming and labor intensive endeavor.
Once an item is strapped to a hand truck and tilted with the framework of the hand truck, it is the responsibility of the handler to balance the object above the wheels of the hand truck. If the center of gravity of the lifted object is not kept balanced over the wheels, the handler must compensate using manual force. If the object is tipped too far, the weight of the object can easily surpass the strength of the handler and both the object and hand truck could fall together.
A need therefore exists for an improved system that can be used to lift and move a heavy object without having to place that object on dollies. A need also exists for a system that could enable a single person to lift and move a large bulky object without assistance. These needs are met by the present invention as described and claimed below.